Golf-ball.



C. DAVIS & F. KNIFFEN.

GOLF BALL. APPLICATIONFILED NOV. 29. I915- Pavtented Oct. 24, 1 916.,

at ballistic which is a compound of a nitrate of cellu- CLJELAND DAVIS, OF THE UNITED STATES NAVY, AND FREDERICK KNIFJFEN, 01F WILMINGTON, DELAWARE; SAID KNIFFIIEN ASSIGNOR T SAID DAVIS.

corn-BALL.

ll ,aeateo.

To all whom it may concern: I

Be it known that we, CLEL'AND DAVIS Commander, U. S. Navy, and FREDERICK KNIFFEN, citizens of the United States, rec siding, respectively, in San Diego, California, and WilmingtomDelaware, have invented certain new and useful 'Improvements in Golf-Balls, (Case,C;) and We do hereby declare the following tobe a-full, to clear, and exact description of the inven tion, such as will enable others-skilled in the art to which it appertains to make and use the same.

Our invention relates to objects of ,an 115 elastic nature, essentially adapted for play-- ing or sport, such as balls which are in tended to be struck by clubs, bats, or similar heavy objects.

The particular embodiment of our inven- 2h tion is a golf ball. I a

The use of celluloid as a coating for golf balls has long been known. This coating is applied either in the form of a paint or varnish so as to hide the dark color of the I .gutta-percha and make the ball itself visible the alternative method is employed, the

= joint between the cups cannot always be made secure, as the celluloid does not always flow and fuse properlyv under pressure. Then, too, it is not always .possible tohave the ball truly centered in the cups.

. eh Thirdly, air, to some extent, may be entrapped between the shoulders and the central body, and may form bubbles which collect at one sideof the ball, thus throwit out of true and interfering with its properties. lEourth, celluloid,

.ose having a low nitration index and camphor, 1s not very strong nor very elastic, and,fmoreover, 1s sub ect to change.

W This change isaccompanied byincreasing brittleness on the part of the cellulose com- ,ound left behind, and sometimes a ten- .ency to scale or crack.

' I We have discovered that those nitro celluloses which have a high index of nitra- Specification of Letters fatent.

otherwise treated, such as nitrated or sulfonated oils.

Patented @ct. a rem.

- Application filed November 29, 1915. Serial No. 64,085.

- tion. We have found that those celluloses which have an index ranging between 11.90 and 12.80, are best in respect as to elasticity and toughness, particularly for our purpose. 7 They, however, are still somewhat too hard .and brittle for use in golf balls and they are slow in responding to a blow.

We find it desirable to modify this nitro cellulose by the addition of some emollient or toughening agent. The one which we prefer to use for the purpose is castor oil.

Castor oil is notliable to oxidation under any conditi0ns,and is generally uniform in quality. We add this to the solution in Which nitro cellulose of the kind indicated has been dissolved. We apprehend that the acid of castor oil, namely, ricinoleic acid, is the efficient agent in this connection, and we may substitute for this oil or its acid, any other corresponding fat or fatty acid,

,such as colza oil, corn oil, soya bean oil,

rape seed oil, or their acids. Other oils of a similar character may be used. We, in fact, are not restricted" to vegetable oils or fats. We prefer not to use an oxidizing oil like linseed oilor tung oil, as these are apt to become resinified in the presence of oxygen. However, under the conditions of use indicated, oxidation progresses with extreme slowness, when the latter oils are used, because the access of oxygen thereto is practically prevented. We may also use oils We prefer to efiect the formation of our golf ball cover by repeated dippings and dryings of the golf ball core or central part with its elastic rubber winding, into a suitable solution of the nitro cellulose. Other means of providing a cover, such as molding into hemispheres and clamping them together, may be used, but the cover made from depositions out of solutions of the nitro cellulose and its modifying agent, the 1 castor oil, give a coating that is entirely.

homogeneous, particularly if in dipping, if

that be the process used, the ball is im-' mersed on the lines of different axes from time to time. i

It is desirable that the solution employed should be one which will deposit, upon evaporation of the solvent, a continuous,v

tough, coherent coating, and preferably the solvent should be one which leaves a film which has a tendency to shrink on drying. When a solvent of this kind is employed, a

certain constrictive pressure is applied to the interior-of the ball, and as the successive coatings are applied this constriction becomes more or less cumulative, so that the interior of the ball is put under rather high compression, while the coating itself is be employed. Other solvents might be used,

suchas amyl acetate, which gives a very, lustrous film. Methyl alcohol is not so good, as it leaves a weak film.

The label and the brambles may be produced on the coating or cover after the successive dippings and dryings have been completed, by the use of a suitable press. Care must be taken in subjecting'any newly covered and, consequently, somewhat tender balls to the efiect of a golf ball press, that the press be not too warm, as this has an apparent tendency to weaken the film.

In the drawing herewith, we have shown an enlarged sectional view of a ball of the kind we have indicated. In this, 1 is the center of the core of the ball which may be any of the usual cores, such as a piece of cork;

.2 is the winding of rubber strips surrounding said core; 3 is the coverlng of nitro cellulose; and 4 the 'so-called brambles on the exterior of the ball formed by pressing the ball in a suitable mold, which brambles are intended to give direction to the ball in its flight.

We have found in practice that the balls constructed as above, possess certain marked peculiarities. Our cover is so hard that it is not dented or scarred by the topping-blows of beginners and dubs. Our cover gives the ball an elasticity whichmakes it respond quickly and powerfully to the heavy impact of a driver, while it is dead on the green to the comparatively slighter blows of the putting iron. That is, the ball provided with a cover made of nitrated cellulose after the manner indicated, has a latent elasticity which responds only to a powerful blow but remains dormant when a lesser blow is high mashie shot, on striking the ground at the end of the carry, the ball has little tendency to bound, but rolls rather dead straight on its course,

Having thus described our invention what we claim and desire to secure by Letters Patent of the United States is:

1'. A golf ball having a cover comprising nitro cellulose of a high index of nitration, and a modifying agent adapted to affect its toughness and elasticity.

2.- A golf ball having a cover composed in part of highly nitrated nitro cellulose modified by the presence therein of a substance adapted to affect its elasticity.

3. An object comprising in its structure nitro cellulose having a nitration index ranging between 11.90 and 12.30, said nitro cellulose having combined therewith an elasticity modifying agent.

1. A golf ball having a cover consisting of amorphous nitro cellulose of a nitration index ranging from 11.90 to 12.30 and a fat. 5., A golf ball having a cover consisting of amorphous nitro cellulose having a high nitration index and a fat, said cover having been deposited upon said ball from successive coatings of a solution of said nitro cellulose and fat in a volatile solvent, which solvent upon eva oration left said cellulose and fat deposits in a smooth, brilliant and constrictive coating.

6. A playing ball having an elastic center and a cover therefor consisting of amorphous nitro cellulose having a high nitration index and a fat, said cover having been deposited upon said ball from successive coatings of a solution of said flitro cellulose and castor oil in a volatile solvent, which solvent upon evaporation left said cellulose and fat deposited in a smooth, brilliant and constrictive coating.

In testimony whereof, we afiix our signatures.

CLELAND DAVIS. FREDERICK KNIFFEN. 

